In certain situations, it can be important to accurately image a sample having a 3D structure with sub-micron or nanoscale features. One example of a 3D structure is an integrated circuit (IC) which refers to a broad category of electronic circuits residing on “chips” that may be further developed as circuit cards and boards. ICs are used in a wide variety of applications where the integrity of the IC is important and where it is necessary to obtain accurate verification of the contents of the IC, or perform a reliability analysis through physical inspection. The integrity and reliability are particularly critical, for example, for ICs used in military applications. Counterfeit or otherwise fake ICs are an increasingly serious problem, particularly when the counterfeit or otherwise fake IC performs at a substandard level in a critical application. Additionally, with ever-advancing technology nodes and decreasing critical dimensions, the potential for failure due to manufacturing variability and manufacturing defects increases correspondingly. To this end, ensuring accurate, reliable, and legitimate IC structure can be critical to ensure precise operation of certain systems, devices, and components. The ability to characterize manufacturing variability and to image and estimate the physical effect of IC degradation processes can potentially provide valuable feedback to IC designers and foundries.
Although the following Detailed Description will proceed with reference being made to illustrative embodiments, many alternatives, modifications, and variations thereof will be apparent in light of the present disclosure.